How much air does an LP85 hold at 2400 PSI?

[CptTightPants21]

I think people on this board know I am a firm believer in fundamentals and fundamental knowledge, but tank markings gets covered in OW, but rarely is it fully enforced/emphasized. It takes reinforcement to truly master the concept and that reinforcement usually doesn't come until AOW, Nitrox, Intro to Tech. I think cooler heads have done well in the thread and let's keep it going.


CaveSloth--basically, an LP tank is only "full" at 2640. There is no danger to filling your tank up to 2640, but if you get a gas filler with a stick up his A55 and he only fills the tank to 2400, you will have less than 85cuft

Water volume is internal volume, not external.

 

[CaveSloth]

Is the tank length 26 inches (not incl the valve)?

The tank length from the rounded bottom on the floor up to the end of the tank, before the chrome valve starts is:

26.5"

Measured twice with 2 different tape measures.

 

[Storker]

If the "water volume" of two tanks (is that the external volume??)

No. It's the internal volume, how much water you can put into the tank.

 

[CaveSloth]

@tursiops any clue as to the 26.5" length of these tanks?

 

[flymolo]

This is a great thread

 

[tursiops]

@tursiops any clue as to the 26.5" length of these tanks?

This is a listing of current Faber tanks, from Blue Steel. Older listings show the same highlighted tank but with a different item number.

If you want to know for sure, you'd take the valve off, fill the tank with water, and measure how much water is in it. I do NOT recommend you do this....

 

[CaveSloth]

Thanks for being decent to me @tursiops

So, no info on a 26.5 length tank or I am measuring the length incorrectly. Anyway, that is close so I will use it for my calculations.

 

[kelemvor]

Without the unnecessary nonsense of tank factors, if the tank holds 85 cuft at 2640, then it holds
(2400/2640) * 85 = 77 cuft at 2400 and (3600/2640) * 85 = 116 cuft at 3600. Simple proportions, at least for an ideal gas, which tanks factors don't accommodate anyway.

I have to agree. The calculation is as simple as a calculation can be. Tank factors add a useless complication.

 

[flymolo]

I have to agree. The calculation is as simple as a calculation can be. Tank factors add a useless complication.

I'm actually confused by this. Isn't the calculation you cited the exact same one that's used to determine "tank factor"?

 

[Bob DBF]

A + sign means it is rated for 10% overfill from its stamped rating, and must be renewed at hydro.

The stamped rating of the tank is known as the tank's service pressure. During hydro the tank can be tested to see if the +rating can be stamped, allowing fills that are 10% higher than the service pressure. Some hydro shops never test for the + rating, so it's a good thing to ask about before having a hydro done.